U.S. patent number 10,418,059 [Application Number 15/371,075] was granted by the patent office on 2019-09-17 for methods for selecting wrap angle for inducing tape tenting above transducer.
This patent grant is currently assigned to International Business Machines Corporation. The grantee listed for this patent is International Business Machines Corporation. Invention is credited to Robert G. Biskeborn, W. Stanley Czarnecki, Calvin S. Lo.
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United States Patent |
10,418,059 |
Biskeborn , et al. |
September 17, 2019 |
Methods for selecting wrap angle for inducing tape tenting above
transducer
Abstract
In one general embodiment, a method includes determining a
distance from a transducer of a module to an edge of the module
closest thereto, and selecting a wrap angle based on the determined
distance for inducing tenting of a moving magnetic recording tape
in a region above the transducer. In another general embodiment, a
method includes running a magnetic recording tape over a tape
bearing surface having at least one edge, and detecting signals
from the tape at differing wrap angles for estimating a height of
tenting of the tape above a transducer at each of the wrap angles.
A wrap angle is selected to provide about a predefined height of
tenting of the tape above the transducer.
Inventors: |
Biskeborn; Robert G.
(Hollister, CA), Czarnecki; W. Stanley (Palo Alto, CA),
Lo; Calvin S. (Saratoga, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
International Business Machines Corporation |
Armonk |
NY |
US |
|
|
Assignee: |
International Business Machines
Corporation (Armonk, NY)
|
Family
ID: |
62243793 |
Appl.
No.: |
15/371,075 |
Filed: |
December 6, 2016 |
Prior Publication Data
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|
|
|
Document
Identifier |
Publication Date |
|
US 20180158478 A1 |
Jun 7, 2018 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G11B
5/1871 (20130101); G11B 15/64 (20130101); G11B
5/255 (20130101); G11B 5/00826 (20130101); G11B
15/60 (20130101); G11B 15/62 (20130101); G11B
5/00813 (20130101); G11B 15/43 (20130101); G11B
5/4893 (20130101); G11B 5/60 (20130101); G11B
5/187 (20130101) |
Current International
Class: |
G11B
15/62 (20060101); G11B 5/008 (20060101); G11B
5/48 (20060101); G11B 5/255 (20060101); G11B
5/187 (20060101); G11B 15/60 (20060101); G11B
5/60 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1167625 |
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Oct 1969 |
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GB |
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55150126 |
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Nov 1980 |
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JP |
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2015005926 |
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Jan 2015 |
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WO |
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Primary Examiner: Klimowicz; William J
Attorney, Agent or Firm: Zilka-Kotab, P.C.
Claims
What is claimed is:
1. A method, comprising: determining a distance from a transducer
of a module to an edge of the module closest thereto; and selecting
a wrap angle based on the determined distance for inducing tenting
of a moving magnetic recording tape directly above the transducer
whereby a resulting tent of the moving magnetic recording tape
extends from the edge of the module closest thereto to a minima
with a tent apex therebetween, wherein the minima is at a first
point of closest approach of the moving magnetic recording tape to
a tape bearing surface of the module nearest the tent apex, wherein
the determined distance from a location of the transducer on the
tape bearing surface to the edge of the module closest thereto is
less than the length from a location directly under the tent apex
to the edge of the module closest thereto.
2. A method as recited in claim 1, comprising positioning a guide
to set the selected wrap angle.
3. A method as recited in claim 1, comprising positioning a second
module to set the selected wrap angle.
4. A method as recited in claim 1, wherein the distance is measured
optically.
5. A method as recited in claim 1, wherein the distance is measured
mechanically.
6. A method as recited in claim 1, wherein the wrap angle is
selected to produce a predetermined tenting characteristic.
7. A method as recited in claim 6, wherein the tenting
characteristic is a height of the tent apex.
8. A method as recited in claim 7, wherein the height of the tent
apex is in a range of from about 5 to about 30 nanometers from a
media facing surface of a tape support surface.
9. A method as recited in claim 8, wherein the transducer is
recessed from a plane of the media facing surface, wherein the
height of the tent apex is in a range of from about 5 to about 30
nanometers from the transducer.
10. A method as recited in claim 6, wherein the tenting
characteristic is a length of a tent.
11. A method as recited in claim 6, comprising moving the tape over
the module for an amount of time sufficient to cause detectable
wear on the edge; and adjusting the wrap angle to produce the
predetermined tenting characteristic.
12. A method as recited in claim 1, wherein the wrap angle is
selected to provide about a predefined height of tenting of the
moving magnetic recording tape above a tape bearing surface of the
transducer.
13. A method as recited in claim 12, wherein a tape bearing surface
of the module is planar.
14. A method as recited in claim 1, wherein the transducer is a TMR
sensor.
15. A computer program product for determining a wrap angle, the
computer program product comprising a computer readable storage
medium having program instructions embodied therewith, wherein the
computer readable storage medium is not a transitory signal per se,
the program instructions executable by a processor to cause the
processor to perform a method comprising: determining, by the
processor, a distance from a transducer of a module to an edge of
the module closest thereto; and, selecting, by the processor, a
wrap angle based on the determined distance for inducing tenting of
a moving magnetic recording tape directly above the transducer
whereby a resulting tent of the moving magnetic recording tape
extends from the edge of the module closest thereto to a minima
with a tent apex therebetween, wherein the minima is at a first
point of closest approach of the moving magnetic recording tape to
a tape bearing surface of the module nearest the tent apex, wherein
the determined distance from a location of the transducer on the
tape bearing surface to the edge of the module closest thereto is
less than the length from a location directly under the tent apex
to the edge of the module closest thereto.
16. A computer program product as recited in claim 15, comprising
positioning, by the processor, a guide to set the selected wrap
angle.
17. A computer program product as recited in claim 15, comprising
positioning, by the processor, a second module to set the selected
wrap angle.
18. A computer program product as recited in claim 15, wherein the
distance is measured optically.
19. A computer program product as recited in claim 15, wherein the
wrap angle is selected to produce a predetermined tenting
characteristic.
20. A computer program product as recited in claim 19, wherein the
tenting characteristic is a height of the tent apex.
21. A computer program product as recited in claim 20, wherein the
height of the tent apex is in a range of from about 5 to about 30
nanometers from a media facing surface of a tape support
surface.
22. A computer program product as recited in claim 15, wherein the
wrap angle is selected to provide about a predefined height of
tenting of the moving magnetic recording tape above a tape bearing
surface of the transducer.
Description
BACKGROUND
The present invention relates to data storage systems, and more
particularly, this invention relates to magnetic tape heads, more
particularly, to setting the wrap angle for optimal spacing between
the transducers and the tape.
In magnetic storage systems, magnetic transducers read data from
and write data onto magnetic recording media. Data is written on
the magnetic recording media by moving a magnetic recording
transducer to a position over the media where the data is to be
stored. The magnetic recording transducer then generates a magnetic
field, which encodes the data into the magnetic media. Data is read
from the media by similarly positioning the magnetic read
transducer and then sensing the magnetic field of the magnetic
media. Read and write operations may be independently synchronized
with the movement of the media to ensure that the data can be read
from and written to the desired location on the media.
An important and continuing goal in the data storage industry is
that of increasing the density of data stored on a medium. For tape
storage systems, that goal has led to increasing the track and
linear bit density on recording tape, and decreasing the thickness
of the magnetic tape medium. However, the development of small
footprint, higher performance tape drive systems has created
various problems in the design of a tape head assembly for use in
such systems.
In a tape drive system, the drive moves the magnetic tape over the
surface of the tape head at high speed. Usually the tape head is
designed to minimize the spacing between the head and the tape. The
spacing between the magnetic head and the magnetic tape is crucial
and so goals in these systems are to have the recording gaps of the
transducers, which are the source of the magnetic recording flux in
near contact with the tape to effect writing sharp transitions, and
to have the read elements in near contact with the tape to provide
effective coupling of the magnetic field from the tape to the read
elements.
SUMMARY
A method according to one embodiment includes determining a
distance from a transducer of a module to an edge of the module
closest thereto, and selecting a wrap angle based on the determined
distance for inducing tenting of a moving magnetic recording tape
in a region above the transducer.
A method according to another embodiment includes running a
magnetic recording tape over a tape bearing surface having at least
one edge, and detecting signals from the tape at differing wrap
angles for estimating a height of tenting of the tape above a
transducer at each of the wrap angles. A wrap angle is selected to
provide about a predefined height of tenting of the tape above the
transducer.
A computer program product for determining a wrap angle, according
to one embodiment, includes a computer readable storage medium
having program instructions embodied therewith, where the computer
readable storage medium is not a transitory signal per se. The
program instructions are executable by a processor to cause the
processor to perform a method that includes receiving, by the
processor, a measurement of a distance from an edge to a
transducer. The method also includes receiving, by the processor, a
predefined height of tenting of a magnetic recording tape above the
transducer, and determining, by the processor, a wrap angle for
inducing tenting of the magnetic recording tape above the
transducer at the predefined height when the magnetic recording
tape passes over the edge in a direction of tape travel
thereacross.
Any of these embodiments may be implemented in a magnetic data
storage system such as a tape drive system, which may include a
magnetic head, a drive mechanism for passing a magnetic medium
(e.g., recording tape) over the magnetic head, and a controller
electrically coupled to the magnetic head.
Other aspects and embodiments of the present invention will become
apparent from the following detailed description, which, when taken
in conjunction with the drawings, illustrate by way of example the
principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a schematic diagram of a simplified tape drive system
according to one embodiment.
FIG. 1B is a schematic diagram of a tape cartridge according to one
embodiment.
FIG. 2 illustrates a side view of a flat-lapped, bi-directional,
two-module magnetic tape head according to one embodiment.
FIG. 2A is a tape bearing surface view taken from Line 2A of FIG.
2.
FIG. 2B is a detailed view taken from Circle 2B of FIG. 2A.
FIG. 2C is a detailed view of a partial tape bearing surface of a
pair of modules.
FIG. 3 is a partial tape bearing surface view of a magnetic head
having a write-read-write configuration.
FIG. 4 is a partial tape bearing surface view of a magnetic head
having a read-write-read configuration.
FIG. 5 is a side view of a magnetic tape head with three modules
according to one embodiment where the modules all generally lie
along about parallel planes.
FIG. 6 is a side view of a magnetic tape head with three modules in
a tangent (angled) configuration.
FIGS. 7A-7C are schematics depicting the principles of tape
tenting.
FIG. 8A is a side cross-sectional view of a magnetic tape head
according to one embodiment.
FIG. 8B is a detailed view of circle 8B of FIG. 8A according to one
embodiment.
FIG. 9A is a flow chart of a method according to one
embodiment.
FIG. 9B is a flow chart of a method according to one
embodiment.
FIG. 10 is a graphic example of wrap angle selection based on
transducer position and tent height according to various
embodiments.
FIG. 11 is a graphic example of wrap angle selection based on
transducer position and tent height according to various
embodiments.
FIG. 12 is a flow chart of a method according to one
embodiment.
FIG. 13 is a flow chart of a method according to one
embodiment.
DETAILED DESCRIPTION
The following description is made for the purpose of illustrating
the general principles of the present invention and is not meant to
limit the inventive concepts claimed herein. Further, particular
features described herein can be used in combination with other
described features in each of the various possible combinations and
permutations.
Unless otherwise specifically defined herein, all terms are to be
given their broadest possible interpretation including meanings
implied from the specification as well as meanings understood by
those skilled in the art and/or as defined in dictionaries,
treatises, etc.
It must also be noted that, as used in the specification and the
appended claims, the singular forms "a," "an" and "the" include
plural referents unless otherwise specified.
The following description discloses several preferred embodiments
of magnetic storage systems, as well as operation and/or component
parts thereof.
In one general embodiment, a method includes determining a distance
from a transducer of a module to an edge of the module closest
thereto, and selecting a wrap angle based on the determined
distance for inducing tenting of a moving magnetic recording tape
in a region above the transducer.
In another general embodiment, a method includes running a magnetic
recording tape over a tape bearing surface having at least one
edge, and detecting signals from the tape at differing wrap angles
for estimating a height of tenting of the tape above a transducer
at each of the wrap angles. A wrap angle is selected to provide
about a predefined height of tenting of the tape above the
transducer.
In another general embodiment, a computer program product for
determining a wrap angle includes a computer readable storage
medium having program instructions embodied therewith, where the
computer readable storage medium is not a transitory signal per se.
The program instructions are executable by a processor to cause the
processor to perform a method that includes receiving, by the
processor, a measurement of a distance from an edge to a
transducer. The method also includes receiving, by the processor, a
predefined height of tenting of a magnetic recording tape above the
transducer, and determining, by the processor, a wrap angle for
inducing tenting of the magnetic recording tape above the
transducer at the predefined height when the magnetic recording
tape passes over the edge in a direction of tape travel
thereacross.
FIG. 1A illustrates a simplified tape drive 100 of a tape-based
data storage system, which may be employed in the context of the
present invention. While one specific implementation of a tape
drive is shown in FIG. 1A, it should be noted that the embodiments
described herein may be implemented in the context of any type of
tape drive system.
As shown, a tape supply cartridge 120 and a take-up reel 121 are
provided to support a tape 122. One or more of the reels may form
part of a removable cartridge and are not necessarily part of the
system 100. The tape drive, such as that illustrated in FIG. 1A,
may further include drive motor(s) to drive the tape supply
cartridge 120 and the take-up reel 121 to move the tape 122 over a
tape head 126 of any type. Such head may include an array of
readers, writers, or both.
Guides 125 guide the tape 122 across the tape head 126. Such tape
head 126 is in turn coupled to a controller 128 via a cable 130.
The controller 128, may be or include a processor and/or any logic
for controlling any subsystem of the drive 100. For example, the
controller 128 typically controls head functions such as servo
following, data writing, data reading, etc. The controller 128 may
include at least one servo channel and at least one data channel,
each of which include data flow processing logic configured to
process and/or store information to be written to and/or read from
the tape 122. The controller 128 may operate under logic known in
the art, as well as any logic disclosed herein, and thus may be
considered as a processor for any of the descriptions of tape
drives included herein, in various embodiments. The controller 128
may be coupled to a memory 136 of any known type, which may store
instructions executable by the controller 128. Moreover, the
controller 128 may be configured and/or programmable to perform or
control some or all of the methodology presented herein. Thus, the
controller 128 may be considered to be configured to perform
various operations by way of logic programmed into one or more
chips, modules, and/or blocks; software, firmware, and/or other
instructions being available to one or more processors; etc., and
combinations thereof.
The cable 130 may include read/write circuits to transmit data to
the head 126 to be recorded on the tape 122 and to receive data
read by the head 126 from the tape 122. An actuator 132 controls
position of the head 126 relative to the tape 122.
An interface 134 may also be provided for communication between the
tape drive 100 and a host (internal or external) to send and
receive the data and for controlling the operation of the tape
drive 100 and communicating the status of the tape drive 100 to the
host, all as will be understood by those of skill in the art.
FIG. 1B illustrates an exemplary tape cartridge 150 according to
one embodiment. Such tape cartridge 150 may be used with a system
such as that shown in FIG. 1A. As shown, the tape cartridge 150
includes a housing 152, a tape 122 in the housing 152, and a
nonvolatile memory 156 coupled to the housing 152. In some
approaches, the nonvolatile memory 156 may be embedded inside the
housing 152, as shown in FIG. 1B. In more approaches, the
nonvolatile memory 156 may be attached to the inside or outside of
the housing 152 without modification of the housing 152. For
example, the nonvolatile memory may be embedded in a self-adhesive
label 154. In one preferred embodiment, the nonvolatile memory 156
may be a Flash memory device, ROM device, etc., embedded into or
coupled to the inside or outside of the tape cartridge 150. The
nonvolatile memory is accessible by the tape drive and the tape
operating software (the driver software), and/or another
device.
By way of example, FIG. 2 illustrates a side view of a flat-lapped,
bi-directional, two-module magnetic tape head 200 which may be
implemented in the context of the present invention. As shown, the
head includes a pair of bases 202, each equipped with a module 204,
and fixed at a small angle .alpha. with respect to each other. The
bases may be "U-beams" that are adhesively coupled together. Each
module 204 includes a substrate 204A and a closure 204B with a thin
film portion, commonly referred to as a "gap" in which the readers
and/or writers 206 are formed. In use, a tape 208 is moved over the
modules 204 along a media (tape) bearing surface 209 in the manner
shown for reading and writing data on the tape 208 using the
readers and writers.
The substrates 204A are typically constructed of a wear resistant
material, such as a ceramic. The closures 204B may be made of the
same or similar ceramic as the substrates 204A.
The readers and writers may be arranged in a piggyback or merged
configuration. An illustrative piggybacked configuration comprises
a (magnetically inductive) writer transducer on top of (or below) a
(magnetically shielded) reader transducer (e.g., a magnetoresistive
reader, etc.), wherein the poles of the writer and the shields of
the reader are generally separated. An illustrative merged
configuration comprises one reader shield in the same physical
layer as one writer pole (hence, "merged"). The readers and writers
may also be arranged in an interleaved configuration.
Alternatively, each array of channels may be readers or writers
only. Any of these arrays may contain one or more servo track
readers for reading servo data on the medium.
FIG. 2A illustrates the tape bearing surface 209 of one of the
modules 204 taken from Line 2A of FIG. 2. A representative tape 208
is shown in dashed lines. The module 204 is preferably long enough
to be able to support the tape as the head steps between data
bands.
In this example, the tape 208 includes 4 to 32 data bands, e.g.,
with 16 data bands and 17 servo tracks 210, as shown in FIG. 2A on
a one-half inch wide tape 208. The data bands are defined between
servo tracks 210. Each data band may include a number of data
tracks, for example 1024 data tracks (not shown). During read/write
operations, the readers and/or writers 206 are positioned to
specific track positions within one of the data bands. Outer
readers, sometimes called servo readers, read the servo tracks 210.
The servo signals are in turn used to keep the readers and/or
writers 206 aligned with a particular set of tracks during the
read/write operations.
FIG. 2B depicts a plurality of readers and/or writers 206 formed in
a gap 218 on the module 204 in Circle 2B of FIG. 2A. As shown, the
array of readers and writers 206 includes, for example, 16 writers
214, 16 readers 216 and two servo readers 212, though the number of
elements may vary. Illustrative embodiments include 8, 16, 32, 40,
and 64 active readers and/or writers 206 per array, and
alternatively interleaved designs having odd numbers of reader or
writers such as 17, 25, 33, etc. An illustrative embodiment
includes 32 readers per array and/or 32 writers per array, where
the actual number of transducer elements could be greater, e.g.,
33, 34, etc. This allows the tape to travel more slowly, thereby
reducing speed-induced tracking and mechanical difficulties and/or
execute fewer "wraps" to fill or read the tape. While the readers
and writers may be arranged in a piggyback configuration as shown
in FIG. 2B, the readers 216 and writers 214 may also be arranged in
an interleaved configuration. Alternatively, each array of readers
and/or writers 206 may be readers or writers only, and the arrays
may contain one or more servo readers 212. As noted by considering
FIGS. 2 and 2A-B together, each module 204 may include a
complementary set of readers and/or writers 206 for such things as
bi-directional reading and writing, read-while-write capability,
backward compatibility, etc.
FIG. 2C shows a partial tape bearing surface view of complementary
modules of a magnetic tape head 200 according to one embodiment. In
this embodiment, each module has a plurality of read/write (R/W)
pairs in a piggyback configuration formed on a common substrate
204A and an optional electrically insulative layer 236. The
writers, exemplified by the write transducer 214 and the readers,
exemplified by the read transducer 216, are aligned parallel to an
intended direction of travel of a tape medium thereacross to form
an R/W pair, exemplified by the R/W pair 222. Note that the
intended direction of tape travel is sometimes referred to herein
as the direction of tape travel, and such terms may be used
interchangeably. Such direction of tape travel may be inferred from
the design of the system, e.g., by examining the guides; observing
the actual direction of tape travel relative to the reference
point; etc. Moreover, in a system operable for bi-direction reading
and/or writing, the direction of tape travel in both directions is
typically parallel and thus both directions may be considered
equivalent to each other.
Several R/W pairs 222 may be present, such as 8, 16, 32 pairs, etc.
The R/W pairs 222 as shown are linearly aligned in a direction
generally perpendicular to a direction of tape travel thereacross.
However, the pairs may also be aligned diagonally, etc. Servo
readers 212 are positioned on the outside of the array of R/W
pairs, the function of which is well known.
Generally, the magnetic tape medium moves in either a forward or
reverse direction as indicated by arrow 220. The magnetic tape
medium and head assembly 200 operate in a transducing relationship
in the manner well-known in the art. The piggybacked MR head
assembly 200 includes two thin-film modules 224 and 226 of
generally identical construction.
Modules 224 and 226 are joined together with a space present
between closures 204B thereof (partially shown) to form a single
physical unit to provide read-while-write capability by activating
the writer of the leading module and reader of the trailing module
aligned with the writer of the leading module parallel to the
direction of tape travel relative thereto. When a module 224, 226
of a piggyback head 200 is constructed, layers are formed in the
gap 218 created above an electrically conductive substrate 204A
(partially shown), e.g., of AlTiC, in generally the following order
for the R/W pairs 222: an insulating layer 236, a first shield 232
typically of an iron alloy such as NiFe (-), cobalt zirconium
tantalum (CZT) or Al--Fe--Si (Sendust), a sensor 234 for sensing a
data track on a magnetic medium, a second shield 238 typically of a
nickel-iron alloy (e.g., .about.80/20 at % NiFe, also known as
permalloy), first and second writer pole tips 228, 230, and a coil
(not shown). The sensor may be of any known type, including those
based on MR, GMR, AMR, tunneling magnetoresistance (TMR), etc.
The first and second writer poles 228, 230 may be fabricated from
high magnetic moment materials such as .about.45/55 NiFe. Note that
these materials are provided by way of example only, and other
materials may be used. Additional layers such as insulation between
the shields and/or pole tips and an insulation layer surrounding
the sensor may be present. Illustrative materials for the
insulation include alumina and other oxides, insulative polymers,
etc.
The configuration of the tape head 126 according to one embodiment
includes multiple modules, preferably three or more. In a
write-read-write (W-R-W) head, outer modules for writing flank one
or more inner modules for reading. Referring to FIG. 3, depicting a
W-R-W configuration, the outer modules 252, 256 each include one or
more arrays of writers 260. The inner module 254 of FIG. 3 includes
one or more arrays of readers 258 in a similar configuration.
Variations of a multi-module head include a R-W-R head (FIG. 4), a
R-R-W head, a W-W-R head, etc. In yet other variations, one or more
of the modules may have read/write pairs of transducers. Moreover,
more than three modules may be present. In further approaches, two
outer modules may flank two or more inner modules, e.g., in a
W-R-R-W, a R-W-W-R arrangement, etc. For simplicity, a W-R-W head
is used primarily herein to exemplify embodiments of the present
invention. One skilled in the art apprised with the teachings
herein will appreciate how permutations of the present invention
would apply to configurations other than a W-R-W configuration.
FIG. 5 illustrates a magnetic head 126 according to one embodiment
of the present invention that includes first, second and third
modules 302, 304, 306 each having a tape bearing surface 308, 310,
312 respectively, which may be flat, contoured, etc. Note that
while the term "tape bearing surface" appears to imply that the
surface facing the tape 315 is in physical contact with the tape
bearing surface, this is not necessarily the case. Rather, only a
portion of the tape may be in contact with the tape bearing
surface, constantly or intermittently, with other portions of the
tape riding (or "flying") above the tape bearing surface on a layer
of air, sometimes referred to as an "air bearing". The first module
302 will be referred to as the "leading" module as it is the first
module encountered by the tape in a three module design for tape
moving in the indicated direction. The third module 306 will be
referred to as the "trailing" module. The trailing module follows
the middle module and is the last module seen by the tape in a
three module design. The leading and trailing modules 302, 306 are
referred to collectively as outer modules. Also, note that the
outer modules 302, 306 will alternate as leading modules, depending
on the direction of travel of the tape 315.
In one embodiment, the tape bearing surfaces 308, 310, 312 of the
first, second and third modules 302, 304, 306 lie on about parallel
planes (which is meant to include parallel and nearly parallel
planes, e.g., between parallel and tangential as in FIG. 6), and
the tape bearing surface 310 of the second module 304 is above the
tape bearing surfaces 308, 312 of the first and third modules 302,
306. As described below, this has the effect of creating the
desired wrap angle relative to the tape bearing surface 310 of the
second module 304.
Where the tape bearing surfaces 308, 310, 312 lie along parallel or
nearly parallel yet offset planes, intuitively, the tape should
peel off of the tape bearing surface 308 of the leading module 302.
However, the vacuum created by the skiving edge 318 of the leading
module 302 has been found by experimentation to be sufficient to
keep the tape adhered to the tape bearing surface 308 of the
leading module 302. The trailing edge 320 of the leading module 302
(the end from which the tape leaves the leading module 302) is the
approximate reference point which defines the wrap angle of the
second module 304. The tape stays in close proximity to the tape
bearing surface until close to the trailing edge 320 of the leading
module 302. Accordingly, read and/or write elements 322 may be
located near the trailing edges of the outer modules 302, 306.
These embodiments are particularly adapted for write-read-write
applications.
A benefit of this and other embodiments described herein is that,
because the outer modules 302, 306 are fixed at a determined offset
from the second module 304, the inner wrap angle is fixed when the
modules 302, 304, 306 are coupled together or are otherwise fixed
into a head. The inner wrap angle is approximately
tan.sup.-1(.delta./W) where .delta. is the height difference
between the planes of the tape bearing surfaces 308, 310 and W is
the width between the opposing ends of the tape bearing surfaces
308, 310. An illustrative inner wrap angle is in a range of about
0.3.degree. to about 1.1.degree., though can be any angle required
by the design.
Beneficially, the inner wrap angle on the side of the module 304
receiving the tape (leading edge) will be larger than the inner
wrap angle on the trailing edge, as the tape 315 rides above the
trailing module 306. This difference is generally beneficial as a
smaller tends to oppose what has heretofore been a steeper exiting
effective wrap angle.
Note that the tape bearing surfaces 308, 312 of the outer modules
302, 306 are positioned to achieve a negative wrap angle at the
trailing edge 320 of the leading module 302. This is generally
beneficial in helping to reduce friction due to contact with the
trailing edge 320, provided that proper consideration is given to
the location of the crowbar region that forms in the tape where it
peels off the head. This negative wrap angle also reduces flutter
and scrubbing damage to the elements on the leading module 302.
Further, at the trailing module 306, the tape 315 flies over the
tape bearing surface 312 so there is virtually no wear on the
elements when tape is moving in this direction. Particularly, the
tape 315 entrains air and so will not significantly ride on the
tape bearing surface 312 of the third module 306 (some contact may
occur). This is permissible, because the leading module 302 is
writing while the trailing module 306 is idle.
Writing and reading functions are performed by different modules at
any given time. In one embodiment, the second module 304 includes a
plurality of data and optional servo readers 331 and no writers.
The first and third modules 302, 306 include a plurality of writers
322 and no data readers, with the exception that the outer modules
302, 306 may include optional servo readers. The servo readers may
be used to position the head during reading and/or writing
operations. The servo reader(s) on each module are typically
located towards the end of the array of readers or writers.
By having only readers or side by side writers and servo readers in
the gap between the substrate and closure, the gap length can be
substantially reduced. Typical heads have piggybacked readers and
writers, where the writer is formed above each reader. A typical
gap is 20-35 microns. However, irregularities on the tape may tend
to droop into the gap and create gap erosion. Thus, the smaller the
gap is the better. The smaller gap enabled herein exhibits fewer
wear related problems.
In some embodiments, the second module 304 has a closure, while the
first and third modules 302, 306 do not have a closure. Where there
is no closure, preferably a hard coating is added to the module.
One preferred coating is diamond-like carbon (DLC).
In the embodiment shown in FIG. 5, the first, second, and third
modules 302, 304, 306 each have a closure 332, 334, 336, which
extends the tape bearing surface of the associated module, thereby
effectively positioning the read/write elements away from the edge
of the tape bearing surface. The closure 332 on the second module
304 can be a ceramic closure of a type typically found on tape
heads. The closures 334, 336 of the first and third modules 302,
306, however, may be shorter than the closure 332 of the second
module 304 as measured parallel to a direction of tape travel over
the respective module. This enables positioning the modules closer
together. One way to produce shorter closures 334, 336 is to lap
the standard ceramic closures of the second module 304 an
additional amount. Another way is to plate or deposit thin film
closures above the elements during thin film processing. For
example, a thin film closure of a hard material such as Sendust or
nickel-iron alloy (e.g., 45/55) can be formed on the module.
With reduced-thickness ceramic or thin film closures 334, 336 or no
closures on the outer modules 302, 306, the write-to-read gap
spacing can be reduced to less than about 1 mm, e.g., about 0.75
mm, or 50% less than commonly-used Linear Tape Open (LTO) tape head
spacing. The open space between the modules 302, 304, 306 can still
be set to approximately 0.5 to 0.6 mm, which in some embodiments is
ideal for stabilizing tape motion over the second module 304.
Depending on tape tension and tape bending stiffness, it may be
desirable to angle the tape bearing surfaces of the outer modules
relative to the tape bearing surface of the second module. FIG. 6
illustrates an embodiment where the modules 302, 304, 306 are in a
tangent or nearly tangent (angled) configuration. Particularly, the
tape bearing surfaces of the outer modules 302, 306 are about
parallel to the tape at the desired wrap angle at the second module
304. In other words, the planes of the tape bearing surfaces 308,
312 of the outer modules 302, 306 are oriented at about the desired
wrap angle relative to the second module 304. The tape will also
pop off of the trailing module 306 in this embodiment, thereby
reducing wear on the elements in the trailing module 306. These
embodiments are particularly useful for write-read-write
applications. Additional aspects of these embodiments are similar
to those given above.
Typically, the tape wrap angles may be set about midway between the
embodiments shown in FIGS. 5 and 6.
Additional aspects of the embodiments shown in FIG. 6 are similar
to those given above.
A 32 channel version of a multi-module head 126 may use cables 350
having leads on the same or smaller pitch as current 16 channel
piggyback LTO modules, or alternatively the connections on the
module may be organ-keyboarded for a 50% reduction in cable span.
Over-under, writing pair unshielded cables may be used for the
writers, which may have integrated servo readers.
The outer wrap angles may be set in the drive, such as by guides of
any type known in the art, such as adjustable rollers, slides, etc.
or alternatively by outriggers, which are integral to the head. For
example, rollers having an offset axis may be used to set the wrap
angles. The offset axis creates an orbital arc of rotation,
allowing precise alignment of the wrap angle.
To assemble any of the embodiments described above, conventional
u-beam assembly can be used. Accordingly, the mass of the resultant
head may be maintained or even reduced relative to heads of
previous generations. In other approaches, the modules may be
constructed as a unitary body. Those skilled in the art, armed with
the present teachings, will appreciate that other known methods of
manufacturing such heads may be adapted for use in constructing
such heads. Moreover, unless otherwise specified, processes and
materials of types known in the art may be adapted for use in
various embodiments in conformance with the teachings herein, as
would become apparent to one skilled in the art upon reading the
present disclosure.
Conventionally, limitations on areal density are imposed by loss of
signal quality due to increase in head-media spacing resulting from
head wear, or from deposits or other buildup on the head surface. A
method used by the industry to counter the effects of head wear
includes pre-recessing and coating the magnetic head. However,
pre-recession and coating increase magnetic spacing between the
tape and the surface of the sensor and may limit achievable
recording linear density.
A longer tape bearing surface between the edges of a module may
enable minimal tape-to-head spacing in order to improve resolution
and signal output. Specifically, a longer tape bearing surface
creates a middle region of the tape bearing surface for the tape to
couple with between regions of tenting created by the tape at each
edge of the module. However, in TMR heads, minimal spacing between
tape and the tape bearing surface of the sensor may result in
shorting of the sensor by the passing tape. Unfortunately, shorting
of the TMR sensor has the capability to render a TMR sensor
partially to completely non-functional.
Particularly, defects in the magnetic medium may cause shorting
across the sensor. Conventionally, pre-recessed sensors with very
hard coatings on the media bearing surfaces help mitigate wear and
shorting due to defects in the magnetic medium passing over the
sensor. However, under severe conditions, such as large defects
embedded in the media, shorting may still occur in these heads.
Moreover, coatings may be susceptible to wear by the tape and thus
become less protective over time.
Methods such as pre-recession of the recording gap and/or coating
on the tape bearing surface may also be used to control head-tape
spacing. However, neither of these methods enables a way to tailor
the spacing according to measured head geometry for each head. In
addition, when the fabrication processes of the module are
complete, there are no previously-known methods to make adjustments
to the spacing between the head and tape. Accordingly, because the
spacing has been set in conventional heads may be at a minimal
spacing, the shorting problem of TMR sensors has been a pervasive
barrier to the introduction of TMR to tape recording.
Various embodiments described herein provide, in conjunction with a
head having one or more magnetic transducers such as such as
sensors (e.g., data sensors, servo sensors, Hall effect sensors,
etc.) and/or write transducers (writers) positioned in the tape
tenting region, a method to set the height of a tape above the
magnetic transducer to about a predetermined value that is
approximately independent of variations of head geometry.
Furthermore, it may be desirable to have an approximate predefined
spacing between the tape bearing surface of the magnetic transducer
and the tape because error rate, bit error rate, resolution, and
channel parameters are affected by this spacing.
Moreover, manufacturing processes that define the position of the
edge of the tape bearing surface relative to the magnetic
transducer closest thereto are subject to variation. In other
words, the distance from the edge to the magnetic transducer may be
controlled within 10 .mu.m in some embodiments which may translate
to a variation in spacing between the magnetic transducer and tape
of the order of a few nanometers. Thus, despite the variation in
distances of the magnetic transducer to the edge from head-to-head,
the total spacing between the transducer and the tape can be
controlled to a consistent spacing by adjusting the wrap angle.
FIGS. 7A-7C illustrate the principles of tape tenting. FIG. 7A
shows a module 700 having an upper tape bearing surface 702
extending between opposite edges 704, 706. A stationary tape 708 is
shown wrapping around the edges 704, 706. As shown, the bending
stiffness of the tape 708 lifts the tape off of the tape bearing
surface 702. Tape tension tends to flatten the tape profile, as
shown in FIG. 7A. Where tape tension is minimal, the curvature of
the tape is more parabolic than shown.
FIG. 7B depicts the tape 708 in motion. The leading edge, i.e., the
first edge the tape encounters when moving, may serve to skive air
from the tape, thereby creating a subambient air pressure between
the tape 708 and the tape bearing surface 702. In FIG. 7B, the
leading edge is the left edge and the right edge is the trailing
edge when the tape is moving left to right. As a result,
atmospheric pressure above the tape urges the tape toward the tape
bearing surface 702, thereby creating tape tenting proximate each
of the edges. The tape bending stiffness resists the effect of the
atmospheric pressure, thereby causing the tape tenting proximate
both the leading and trailing edges. Modeling predicts that the two
tents are very similar in shape.
FIG. 7C depicts that the subambient pressure urges the tape 708
toward the tape bearing surface 702 even when a trailing guide 710
is positioned above the plane of the tape bearing surface.
The heads depicted in the FIGS. discussed above may be constructed
to mitigate the occurrence of shorting due to tape defects by
positioning the transducers in a tape tenting region, and then
inducing tape tenting above the transducers using the teachings
presented herein.
While much of the following description refers to a sensor being
present in the tape tenting region, this is done by way of example
only, and any type of transducer may be used in any of the
following embodiments in place of the described sensor.
Moreover, the magnetic transducer(s) in any of the embodiments
described herein may be sensors (e.g., data sensors, servo sensors,
Hall effect sensors, etc.) and/or write transducers (writer). While
much of the following description refers to a sensor being present
in the tape tenting region, this is done by way of example only,
and any type of transducer may be used in any of the embodiments in
place of the described sensor.
The following description describes various embodiments with
reference to figures. Note that the figures are not drawn to scale,
but rather features may have been exaggerated to help exemplify the
descriptions herein.
FIGS. 8A-8B depicts an apparatus 800 in accordance with one
embodiment. As an option, the present apparatus 800 may be
implemented in conjunction with features from any other embodiment
listed herein, such as those described with reference to the other
FIGS. Of course, however, such an apparatus 800 and others
presented herein may be used in various applications and/or in
permutations which may or may not be specifically described in the
illustrative embodiments listed herein. Further, the apparatus 800
presented herein may be used in any desired environment.
As shown in FIG. 8A, tenting may be induced above the sensitive
transducers, thereby minimizing tape-transducer contact forces in
the tenting region. Though the resulting reduced (subambient) air
pressure in the region between the tape 802 and the tape bearing
surface 808 causes atmospheric pressure to urge the tape towards
the tape bearing surface 808, the combination of wrap angle, tape
bending stiffness and tape tension causes the tape 802 to lift from
the tape bearing surface 808 of the module 801 proximate to the
edge 804. Atmospheric pressure then urges the tape toward the tape
bearing surface 808, thereby forming the tenting profile.
Subambient air pressure between the tape and tape bearing surface
808 may be created in any number of ways, such as skiving, active
vacuum, presence of wells, air bleed slots, etc., and at any
location along the tape support surface.
For present purposes, the wrap angle .alpha. is measured between a
plane 835 of the tape bearing surface 808 and a straight line 823
drawn tangent to the tape supporting surface of the guide 860 and
intersecting the edge 804. As shown, the tape tends to bow where it
wraps the edge, and consequently the angle the tape makes relative
to the plane 835 of the tape bearing surface 808 at the edge is
smaller than the wrap angle .alpha..
Any wrap angle .alpha. greater than 0.degree. relative to the plane
835 results in a tent 810 being formed by the moving tape 802
proximate the leading edge 804 of the tape bearing surface 808.
This effect is a function of the wrap angle, tape bending
stiffness, tape surface roughness, tape surface compressibility,
atmospheric pressure, and tape tension, and to a lesser extent,
tape speed. For given geometrical wrap angles, for example, stiffer
tapes tend to produce larger tents 810. Nonetheless, where
conditions such as wrap angle and tape tension are otherwise
identical, tapes of a given type from a particular manufacturer
tend to exhibit a similar tenting profile whereby the tenting
region defined thereunder varies only slightly from tape to tape.
Tapes from different manufacturers and/or generations may exhibit
dissimilar tenting characteristics under otherwise identical
conditions. Fortunately, tenting characteristics are readily
determinable using numerical modeling techniques known to those of
skill in the art, such as Finite Element Modeling (FEM), Finite
Difference Modeling (FDM), etc. and combinations thereof.
Nonetheless, differences in tenting characteristics from tape to
tape in the same generation under otherwise identical conditions
may be considered negligible.
The larger the wrap angle .alpha., the larger the tent 810.
Ultimately, at large enough wrap angle, the forces (atmospheric
pressure) urging the tape 802 towards the tape bearing surface 808
may be overcome and the tape 802 may then decouple from the tape
bearing surface 808. Therefore, the wrap angle .alpha. is
preferably selected to provide the desired tenting without breaking
the vacuum thereunder. In a preferred embodiment of apparatus 800,
the wrap angle .alpha. created by the guide may be in a range of
about 0.1 to about 1.5 degrees.
A guide mechanism 860 may be configured to set a wrap angle .alpha.
of the magnetic recording tape 802 at edge 804 of the module 801.
Another guide mechanism (not shown) may be configured to set the
wrap angle at edge 804. Such guide mechanisms may include, e.g., a
tape guide such as guide 125 of FIG. 1A, a pitch roller, a tension
arm, another module, etc.
Multiple modules may be assembled to form a tape head having an
internal wrap angle that may be selected based on a measurement of
the edge-to-sensor separation for each module.
According to the illustrative embodiment in FIG. 8A, the guide
mechanism 860 may be positioned relative to the edge 804 for
inducing tenting 810 of a magnetic recording tape 802 passing in
the direction 832 of tape travel, where the sensor 809 may be
positioned under the location of the tenting 810. In some
approaches, the guide may be positioned to set a wrap angle of the
magnetic recording tape 802 relative to a plane 835 of the tape
bearing surface 808 that creates the tenting 810 in the moving
tape. In other approaches, the tape bearing surface 808 may be
planar.
In the embodiment of apparatus 800, the module 801 includes a tape
support surface 822 on one side of the thin film region 814 and a
tape support surface 824 on an opposite side of the thin film
region 814, where the tape support surface 822 has a length d. For
example, length d may be the distance from the edge 804 to the
sensor 809. In one embodiment, length d may be in a range of about
5 to about 30 nanometers, but could be higher or lower.
In various embodiments, a media facing side of the sensor 809 may
or may not be recessed from the tape bearing surface 808. In
various approaches, apparatus 800 may or may not include a
conventional wear coating above a tape support surface.
Looking to FIG. 8A-8B, the module 801 preferably includes a thin
film region 814 and a CPP sensor 809 (e.g. such as a TMR sensor,
GMR sensor, etc. of a type known in the art) that are positioned
between the tape support surface 822 and tape support surface
824.
According to some embodiments, the sensor 809 may be configured as
a data sensor for reading data tracks of a magnetic medium. In some
approaches, the apparatus 800 includes one or more arrays of such
data sensors.
According to other embodiments, the sensor 809 may be configured as
a servo pattern reading sensor. For example, the sensor 809 may be
configured as a servo pattern reading sensor where apparatus 800
includes one or more arrays of data sensors and/or writers and one
or more servo pattern reading sensors for reading servo data on a
medium.
In yet another embodiment, a module is comprised of an array of
writer transducers and servo readers. In this case, the servo
readers may be used for sensing and/or for setting the magnetic
spacing in the tent.
FIG. 9A depicts a method 900 for determining a wrap angle to induce
a desired tenting in accordance with one embodiment. As an option,
the present method 900 may be implemented in conjunction with
features from any other embodiment listed herein, such as those
described with reference to the other FIGS. Of course, however,
such a method 900 and others presented herein may be used in
various applications and/or in permutations which may or may not be
specifically described in the illustrative embodiments listed
herein. Further, the method 900 presented herein may be used in any
desired environment.
According to one embodiment as shown in FIG. 9A, method 900
includes a step 902 of determining a distance from an edge to a
sensor of a module. Looking to FIG. 8B which represents the circle
8B in FIG. 8A, a distance d may represent the length of the portion
between the edge 804 and the sensor 809. As illustrated in FIG. 8B,
the media bearing surfaces 808 of the module 801 may be primarily
planar. In embodiments where the media bearing surface 808 of the
module 801 is primarily planar, the planar portions of the media
bearing surface 808 may lie along a common plane 835.
In some approaches, the distance d, from edge 804 to sensor 809 may
be measured mechanically using conventional techniques. For
example, atomic force microscopy and/or stylus profilometry may be
used. This may be done at the time the head is fabricated. In other
approaches, the distance d may be measured optically using
conventional techniques. For example, machine vision may be used.
In one approach, laser or other optical interferometry may be used.
Preferably, the resolution of the optical detector is in the
sub-micron level. In further approaches, the distance may be
determined from a database entry, a lab report, manufacturing data,
etc.
With continued reference to FIG. 9A, method 900 includes a step 904
of selecting a wrap angle for inducing tenting of a magnetic
recording tape in a region above the sensor when the magnetic
recording tape passes over the edge. The wrap angle may be selected
to produce a predetermined tenting characteristic. For example,
looking to FIG. 8B a wrap angle .alpha. may be selected based on
the distance d for inducing a tenting of a magnetic recording tape
802 in a region (e.g. region of tenting 810) above the sensor 809
when the magnetic recording tape 802 passes in direction 832 over
the edge 804.
In various embodiments of method 900, the wrap angle may be
selected to provide desired tenting characteristics that change
with wrap angle.
Looking back to FIG. 8B, one such tenting characteristic may be a
peak height h of a tent 810 formed at a particular wrap angle
.alpha.. In some approaches, the peak height h may be in a range of
from about 5 to about 30 nanometers from a media bearing surface
808 of a tape support surface 822, but could be higher or lower. In
other approaches, the peak height h may be measured from the plane
of the tape support surface of a sensor or from a sensor that is
recessed from the plane of the tape support surface.
In some approaches, the tenting characteristic may be a length of a
tent 810.
Tenting characteristics corresponding to differing wrap angles may
be determined experimentally, e.g., by running a tape over the
module and measuring characteristics; determined via modeling;
extrapolated from experimental or modeled data; etc. Tenting
characteristics may be approximated and/or averaged across several
different types of tapes that are compatible with the module to
select a wrap angle that is a best fit for all types of tape. In
some approaches, the wrap angle may be selected under an assumption
that the tenting characteristics of all tapes suitable for use with
the module behave in a substantially similar manner and therefore
any commercially-available tape may be used in experimentation or
modeling to determine the tenting characteristics.
In another approach, wrap angles may be calculated for each of a
plurality of magnetic recording tapes from different manufacturers
to create a similar desired tent region above the tape bearing
surface of the sensor. The results can be stored in a table and
applied when each particular tape is detected by the drive.
Whichever approach is used to determine a wrap angle, the
determined wrap angle(s) may be output, e.g., for use in
positioning components of a tape drive for creating the desired
wrap angle.
FIG. 9B depicts another method 950 according to another embodiment.
Steps 902 and 904 may be similar to those described in FIG. 9A.
With continued reference to FIG. 9B, method 900 includes a decision
step 905, where a determination is made as whether to move the tape
over the module for an amount of time sufficient to cause wear of
the edge. The wear may be detected using an optical interferometer
or stylus profilometer. If the decision at step 905 is not to run
the tape, the process may end, the process may proceed to decision
908 (described below), etc.
If the decision at step 905 is to run the tape, then the tape is
run. At operation 906, a check is made for changes in one or more
tenting characteristics, e.g., tent height, such as via measuring
signals from the tape, optical interferometry, etc.
If there are no changes, then the process proceeds to decision 907.
If there are changes, the process may return to operation 904,
where the wrap angle may be adjusted to provide the desired tenting
characteristic(s). If there are no significant changes, the method
may proceed to decision 908.
When the method 900 continues to step 908, the final wrap angle is
selected, and may be stored, used to set the wrap angle, etc. As an
option, the selected wrap angle may be set according to any
approach described or suggested herein, such as using a second
module, a guide, etc.
In some approaches, the wrap angle .alpha. may be set in the drive
by dynamic rollers, for example eccentric rollers. The offset axis
creates an orbital arc of rotation, allowing precise alignment of
the wrap angle .alpha.. Alternatively, outriggers of a type known
in the art may be used to set the wrap angle .alpha..
In some embodiments, the wrap angle .alpha. may be set in the
drive. In one approach, a positionable tape head may be used with
fixed rollers. In another approach, the wrap angle .alpha. may be
set by a positionable tape support within the drive. Then the
elements of the drive may be assembled as described above.
Conventional u-beam assembly can be used.
In further embodiments, the wrap angle may be set every time a tape
is loaded. For example, an adjustable wrap angle may be used to
compensate for changes in tent spacing as the head wears. Such
adjustable wrap angle may be effected by adjustable guides, a
positionable head, etc.
Using modeling examples from a Finite Element Modeling (FEM)
technique, the wrap angle to create a desired sensor-to-tape
spacing under a tenting region may be calculated, as demonstrated
in FIG. 10. The distance from the edge 804 to the sensor may be
defined as a distance d. Three exemplary sensor locations are shown
at d.sub.1, d.sub.2, and d.sub.3, respectively. If the desired
sensor-to-tape spacing is defined as the height, h.sub.0, then the
corresponding wrap angle may be determined using these two
variables, h.sub.0 and d. For example, if the sensor is located at
a distance of d.sub.1 from the edge 804, then to achieve the
desired sensor-to-tape spacing, h.sub.0, a calculated wrap angle
may generate a shallower wrap corresponding to the tent 810c. If
the sensor is located at a distance d.sub.2 from the edge 804, then
to achieve the desired sensor-to-tape spacing, h.sub.0, a higher
wrap angle may be calculated to provide a higher tent 810b. In yet
other approaches, if the sensor is located at a distance d.sub.3
from the edge 804, then to achieve the desired sensor-to-tape
spacing, h.sub.0, the wrap angle may be calculated to generate an
even higher tent 810a.
FIG. 11 depicts illustrative sensor positions between the tent apex
805 and the edge 804. Similar methodology as that discussed above
with reference to FIG. 10 may be used to determine the appropriate
wrap angle to achieve the desired sensor-to-tape spacing,
h.sub.0.
FIG. 12 depicts a method 1200 for determining a wrap angle to
induce a desired tenting in accordance with one embodiment. As an
option, the present method 1200 may be implemented in conjunction
with features from any other embodiment listed herein, such as
those described with reference to the other FIGS. Of course,
however, such a method 1200 and others presented herein may be used
in various applications and/or in permutations which may or may not
be specifically described in the illustrative embodiments listed
herein. Further, the method 1200 presented herein may be used in
any desired environment.
As shown in FIG. 12, in one embodiment of method 1200, step 1202
includes running a magnetic recording tape over a tape bearing
surface having at least one edge.
Step 1204 of method 1200 includes detecting signals from the tape
at differing wrap angles for estimating a height of tenting of the
tape above a transducer at each of the wrap angles. The signals may
correspond to data. An extent of spacing is detectable as spacing
loss, and representative of the height of tenting of the tape above
the sensor.
Step 1206 of method 1200 includes selecting a wrap angle to provide
about a predefined height of tenting of the tape above the sensor.
The selected wrap angle may be one of the wrap angles used in step
1204, may be extrapolated from the results of step 1204, etc.
In some approaches, method 1200 may involve positioning a second
module to set the selected wrap angle. In other approaches, method
1200 may involve positioning a guide to set the selected wrap
angle.
In some approaches to method 1200, the wrap angle may be selected
based on a tenting characteristic that changes with wrap angle.
Illustrative tenting characteristics are described above.
Now referring to FIG. 13, a flowchart of a method 1300 for
determining a wrap angle to induce a desired tenting is shown
according to one embodiment. The method 1300 may be performed in
accordance with the present invention in any of the environments
depicted in FIGS. 1-12, among others, in various embodiments. Of
course, more or less operations than those specifically described
in FIG. 13 may be included in method 1300, as would be understood
by one of skill in the art upon reading the present
descriptions.
Each of the steps of the method 1300 may be performed by any
suitable component of the operating environment. For example, in
various embodiments, the method 1300 may be partially or entirely
performed by a controller, a processor, a tape drive, or some other
device having one or more processors therein. The processor, e.g.,
processing circuit(s), chip(s), and/or module(s) implemented in
hardware and/or software, and preferably having at least one
hardware component, may be utilized in any device to perform one or
more steps of the method 1300. Illustrative processors include, but
are not limited to, a CPU, an ASIC, a FPGA, etc., combinations
thereof, or any other suitable computing device known in the
art.
As shown in FIG. 13, method 1300 may initiate with operation 1302
where the processor receives a measurement of the distance from an
edge to a sensor and a predefined height of tenting of a magnetic
recording tape above the sensor. The distance may be measured
optically, such as using autocollimators and/or laser focusing. In
other approaches, the distance may be measured mechanically.
Method 1300 includes operation 1304 in which the processor
determines the wrap angle when the magnetic recording tape passes
in over the edge in the direction of tape travel.
In some embodiments of method 1300, a module of a tape head may be
set in a vertical direction to create the calculated wrap angle
when the magnetic recording tape passes over the edge.
In other embodiments of method 1300, a guide may be set to create
the calculated wrap angle of the magnetic recording tape as the
magnetic recording tape passes over the edge.
The present invention may be a system, a method, and/or a computer
program product. The computer program product may include a
computer readable storage medium (or media) having computer
readable program instructions thereon for causing a processor to
carry out aspects of the present invention.
The computer readable storage medium can be a tangible device that
can retain and store instructions for use by an instruction
execution device. The computer readable storage medium may be, for
example, but is not limited to, an electronic storage device, a
magnetic storage device, an optical storage device, an
electromagnetic storage device, a semiconductor storage device, or
any suitable combination of the foregoing. A non-exhaustive list of
more specific examples of the computer readable storage medium
includes the following: a portable computer diskette, a hard disk,
a random access memory (RAM), a read-only memory (ROM), an erasable
programmable read-only memory (EPROM or Flash memory), a static
random access memory (SRAM), a portable compact disc read-only
memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a
floppy disk, a mechanically encoded device such as punch-cards or
raised structures in a groove having instructions recorded thereon,
and any suitable combination of the foregoing. A computer readable
storage medium, as used herein, is not to be construed as being
transitory signals per se, such as radio waves or other freely
propagating electromagnetic waves, electromagnetic waves
propagating through a waveguide or other transmission media (e.g.,
light pulses passing through a fiber-optic cable), or electrical
signals transmitted through a wire.
Computer readable program instructions described herein can be
downloaded to respective computing/processing devices from a
computer readable storage medium or to an external computer or
external storage device via a network, for example, the Internet, a
local area network, a wide area network and/or a wireless network.
The network may comprise copper transmission cables, optical
transmission fibers, wireless transmission, routers, firewalls,
switches, gateway computers and/or edge servers. A network adapter
card or network interface in each computing/processing device
receives computer readable program instructions from the network
and forwards the computer readable program instructions for storage
in a computer readable storage medium within the respective
computing/processing device.
Computer readable program instructions for carrying out operations
of the present invention may be assembler instructions,
instruction-set-architecture (ISA) instructions, machine
instructions, machine dependent instructions, microcode, firmware
instructions, state-setting data, or either source code or object
code written in any combination of one or more programming
languages, including an object oriented programming language such
as Smalltalk, C++ or the like, and conventional procedural
programming languages, such as the "C" programming language or
similar programming languages. The computer readable program
instructions may execute entirely on the user's computer, partly on
the user's computer, as a stand-alone software package, partly on
the user's computer and partly on a remote computer or entirely on
the remote computer or server. In the latter scenario, the remote
computer may be connected to the user's computer through any type
of network, including a local area network (LAN) or a wide area
network (WAN), or the connection may be made to an external
computer (for example, through the Internet using an Internet
Service Provider). In some embodiments, electronic circuitry
including, for example, programmable logic circuitry,
field-programmable gate arrays (FPGA), or programmable logic arrays
(PLA) may execute the computer readable program instructions by
utilizing state information of the computer readable program
instructions to personalize the electronic circuitry, in order to
perform aspects of the present invention.
Aspects of the present invention are described herein with
reference to flowchart illustrations and/or block diagrams of
methods, apparatus (systems), and computer program products
according to embodiments of the invention. It will be understood
that each block of the flowchart illustrations and/or block
diagrams, and combinations of blocks in the flowchart illustrations
and/or block diagrams, can be implemented by computer readable
program instructions.
These computer readable program instructions may be provided to a
processor of a general purpose computer, special purpose computer,
or other programmable data processing apparatus to produce a
machine, such that the instructions, which execute via the
processor of the computer or other programmable data processing
apparatus, create means for implementing the functions/acts
specified in the flowchart and/or block diagram block or blocks.
These computer readable program instructions may also be stored in
a computer readable storage medium that can direct a computer, a
programmable data processing apparatus, and/or other devices to
function in a particular manner, such that the computer readable
storage medium having instructions stored therein comprises an
article of manufacture including instructions which implement
aspects of the function/act specified in the flowchart and/or block
diagram block or blocks.
The computer readable program instructions may also be loaded onto
a computer, other programmable data processing apparatus, or other
device to cause a series of operational steps to be performed on
the computer, other programmable apparatus or other device to
produce a computer implemented process, such that the instructions
which execute on the computer, other programmable apparatus, or
other device implement the functions/acts specified in the
flowchart and/or block diagram block or blocks.
The flowchart and block diagrams in the Figures illustrate the
architecture, functionality, and operation of possible
implementations of systems, methods, and computer program products
according to various embodiments of the present invention. In this
regard, each block in the flowchart or block diagrams may represent
a module, segment, or portion of instructions, which comprises one
or more executable instructions for implementing the specified
logical function(s). In some alternative implementations, the
functions noted in the block may occur out of the order noted in
the figures. For example, two blocks shown in succession may, in
fact, be executed substantially concurrently, or the blocks may
sometimes be executed in the reverse order, depending upon the
functionality involved. It will also be noted that each block of
the block diagrams and/or flowchart illustration, and combinations
of blocks in the block diagrams and/or flowchart illustration, can
be implemented by special purpose hardware-based systems that
perform the specified functions or acts or carry out combinations
of special purpose hardware and computer instructions.
Moreover, a system according to various embodiments may include a
processor and logic integrated with and/or executable by the
processor, the logic being configured to perform one or more of the
process steps recited herein. By integrated with, what is meant is
that the processor has logic embedded therewith as hardware logic,
such as an application specific integrated circuit (ASIC), a field
programmable gate array (FPGA), etc. By executable by the
processor, what is meant is that the logic is hardware logic;
software logic such as firmware, part of an operating system, part
of an application program; etc., or some combination of hardware
and software logic that is accessible by the processor and
configured to cause the processor to perform some functionality
upon execution by the processor. Software logic may be stored on
local and/or remote memory of any memory type, as known in the art.
Any processor known in the art may be used, such as a software
processor module and/or a hardware processor such as an ASIC, a
FPGA, a central processing unit (CPU), an integrated circuit (IC),
etc.
It will be clear that the various features of the foregoing systems
and/or methodologies may be combined in any way, creating a
plurality of combinations from the descriptions presented
above.
It will be further appreciated that embodiments of the present
invention may be provided in the form of a service deployed on
behalf of a customer.
The inventive concepts disclosed herein have been presented by way
of example to illustrate the myriad features thereof in a plurality
of illustrative scenarios, embodiments, and/or implementations. It
should be appreciated that the concepts generally disclosed are to
be considered as modular, and may be implemented in any
combination, permutation, or synthesis thereof. In addition, any
modification, alteration, or equivalent of the presently disclosed
features, functions, and concepts that would be appreciated by a
person having ordinary skill in the art upon reading the instant
descriptions should also be considered within the scope of this
disclosure.
While various embodiments have been described above, it should be
understood that they have been presented by way of example only,
and not limitation. Thus, the breadth and scope of an embodiment of
the present invention should not be limited by any of the
above-described exemplary embodiments, but should be defined only
in accordance with the following claims and their equivalents.
* * * * *